The present invention relates to a reading pen for reading text, which has an elongate casing with a reading opening formed in one end thereof, a printed circuit board arranged inside the casing, light-emitting diodes arranged inside the reading opening and adapted to illuminate the text that is to be read, and a light-sensitive sensor arranged inside the reading opening and adapted to read the illuminated text.
A reading pen of the type described above is known from SE 9604008-4. It is also sold by the applicant under the trademark C-PEN. The reading pen is intended for selective recording of text from, for instance, books. The recorded text can be stored and edited in the pen. It can also be transmitted in a wireless manner to another computer.
The prior-art reading pen has, among other things, a casing, a light-sensitive sensor, a flexible card, a lens system, a printed circuit board and a reflector.
The casing which is made of a plastic material is designed as a pen with a narrowing end, in which a reading opening is formed, through which the text is read. In the casing there is a display which shows the read text.
The flexible card is a soft and flexible card having a complicated shape. It supports the light-sensitive sensor and a plurality of, usually ten, Light-emitting diodes which are uniformly distributed round an opening in the flexible card. The flexible card is essentially arranged in the narrowing end of the casing.
The lens system, which comprises a lens and a mirror, is placed on top of the light-sensitive sensor. The light-sensitive sensor is arranged perpendicular to the reading opening, and the mirror in the lens system is adapted to reflect the imaged text at an angle of 90 degrees to the light-sensitive sensor.
The printed circuit board is a hard and essentially rectangular card, on which a plurality of components for processing the recorded information are arranged. It is arranged in the casing inside the narrowing end thereof.
When reading text, the text must be illuminated. This is carried out by means of the light-emitting diodes, which have a wavelength corresponding to that to which the light-sensitive sensor is most sensitive. This wavelength is between 500 and 700 nm and corresponds to read light. That part of the flexible card on which the light-emitting diodes are arranged is placed just inside the reading opening so that the opening of the flexible card is positioned opposite to the reading opening. The light-emitting diodes are arranged to illuminate the text through the reading opening, and their light is uniformly reflected by means of the reflector which is placed round the reading opening.
The flexible card, on which the light-sensitive sensor and the light-emitting diodes are arranged, is expensive to manufacture and also difficult and time-consuming to mount, since it must be mounted manually.
The object of the present invention therefore is to provide a sensor/light-emitting-diode arrangement which is easier and less expensive to manufacture.
According to the invention, this object is achieved by means of a reading pen which is of the type stated by way of introduction and has the features that appear from appended claim 1.
More specifically, the invention concerns a reading pen for reading text, which has an elongate casing with a reading opening formed in one end thereof, a printed circuit board which is arranged in the casing, light-emitting diodes arranged inside the reading opening and adapted to illuminate the text which is to be read and a light-sensitive sensor arranged inside the reading opening and adapted to read the illuminated text, the printed circuit board having an end portion at said one end of the casing, said end portion essentially corresponding to the form of the casing, and the light-emitting diodes and the light-sensitive sensor being arranged on said end portion.
In the prior-art technique, the light-emitting diodes are mounted on the flexible card, which is expensive and complicated to mount. According to the invention, the light-emitting diodes are mounted on the printed circuit board. This is made possible by an extension of the hard printed circuit board in one end of the casing. In this way, the expensive flexible card can be omitted. Furthermore, the hard printed circuit board has a higher thermal conductivity then the flexible card. This means that the heat emitted by the light-emitting diodes is better and more efficiently removed.
In a preferred embodiment, a reflector is arranged in the reading opening to reflect and diffusely spread the light emitted by the light-emitting diodes. As a result, the sensor obtains a uniform light and no extra software need be implemented to compensate for a non-uniform luminous flux. Advantageously, the reflector is white and reflects the light in a diffuse way. It is located on the inside of the casing from the position where the light-emitting diodes are located up to the opening.
Preferably, the light-emitting diodes are placed on one large face of the printed circuit board and the light-sensitive sensor is placed on the other large face thereof. This yields a uniform and satisfactory illumination and makes the mounting of the light-emitting diodes and the sensor easier. Additionally it prevents the light emitted from the light-emitting diodes from directly reaching the sensor.
In another preferred embodiment, the light-emitting diodes are arranged on both large faces of the printed circuit board. This gives the mounting of the components of the printed circuit board a higher flexibility, since the light-emitting diodes can be arranged where there is free space. Thus the light-emitting diodes are provided with reflectors that direct the light outward.
In a preferred embodiment, a mirror is arranged to angle the ray path essentially 90 degrees to the surface of the sensor. By angling the ray path essentially 90 degrees a distortion of the reflected light (an image) is avoided. Additionally, use can be made of a plane mirror that is easy to manufacture.
In another preferred embodiment, the light-emitting diodes emit light parallel to the surface of the printed circuit board. By using light-emitting diodes, which angle the ray path of the light essentially 90 degrees, the light-emitting diodes can be arranged directly on the printed circuit board. Accordingly, there is no need for an additional construction to arrange the light-emitting diodes in order to have them emit light through the reading opening of the reading pen.